BIOL412 Chapter Notes - Chapter 33: Vernation, Vascular Cambium, Lycopodiopsida
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Haploid 1n number of chromosomes, result of reduction division (meiosis) Diploid 2n number of chromosomes, result of fusion of haploid nuclei (fertilization) All plants and most animals have an alternation of generations between haploid-diploid stages: Evolution from unicellular to multicellular haploid and diploid stages. Haploid stages of plants are called gametophytes they produce 1n gametes that fuse to 2n. Diploid stages of plants are called sporophytes they produce 2n spores or even 2n seeds. Gametophytes dominant, have leaf-like enations on a stem-like axis and root-like rhizoids. Sporophytes have stomates but are not photosynthetic. Gametophytes (1n) produces two types of gametes in bryophytes. Xylem: conducts water and dissolved minerals upward from the roots. Phloem: conducts sucrose and hormones upward and downward. Conduction of water and metabolites (mainly sugar) enables greater size. Vascular cambium enables development of woody tissue. First vascular plants, have roots, stems, and leaves. Homosporous (same gametophyte) or heterosporous (separate male and female gametophytes)
